In November 1994, the Convention on International Trade in
Endangered Species (CITES) passed a resolution requesting that the Food and
Agriculture Organization of the United Nations (FAO) and other international
organizations to establish programmes to collect and assemble the necessary
biological and trade data on sharks. This CITES resolution reflects the concern
that shark stocks are being depleted rapidly and an attempt must be made to
understand and quantify the effects of the world trade on shark populations. The
purpose of this work is to indicate the species of sharks that may be threatened
by overexploitation or trade, in response to the CITES request. This work lists
all species of sharks that are reported in both commercial and recreational
fisheries throughout the world, and assigns a status category to each, based on
historical fishery trends, on reproductive potential of the species, and on the
impact of fisheries upon the species. The authors believe that a species
approach is the only meaningful and practical approach to shark conservation and
management. Generic compilations of elasmobranch or "shark" landings, although
interesting, convey little understanding of what is happening to species in a
fishery, and are of little practical use in management and conservation
attempts.

1.1 Historical
background

In the early 1980s, political and economic changes throughout
the world affected fishing markets and operations. In particular in China, shark
fins were no longer considered as a luxury product and it led to a significant
growth of domestic consumption thanks also to the reduction of tariff rates on
imported shark fins (Cook 1990, Rose 1996). In other areas, declining catches
and rising prices of traditional food fishes made under-utilized sharks an
inexpensive source of protein. These two factors engendered numerous and diverse
shark fisheries throughout the world. By the late 1980s, shark fisheries
everywhere were growing at a rapid pace fuelled by the demand and the high shark
fin prices. By the mid 1990s, the ex-vessel price for dry shark fins had reached
US $60 per kilogram, providing sufficient incentive to harvest sharks, even when
the meat was not marketable. Currently, shark fisheries encompass the entire
world and catch most large species of coastal and oceanic sharks.

While shark fisheries were growing in the early 1980s, the
pelagic swordfish and tuna longline fisheries were also growing dramatically.
These fisheries normally catch a large proportion of sharks as bycatch. In the
early years of those fisheries, sharks were usually released or discarded. By
the late 1980s, the high price of the fins caused previously released or
discarded sharks to be retained as bycatch, and to be brought on board to be
finned. Today, shark bycatch is probably a significant portion of the total
shark mortality.

The history of the shark fisheries indicates that intensive
fisheries are not sustainable, and that initial exploitation is followed by, at
best, a rapid decline in catch rates or, at worst, by a complete collapse of the
fishery (Holden 1974). Examples of shark fisheries that collapsed are the
California soupfin shark fishery (Ripley 1946), the New England porbeagle
fishery (Casey et al. 1978), the Australian school shark fishery (Olsen
1954), the English basking shark fishery (Parker and Stott 1965), and the
California thresher shark fishery (Cailliet et al. 1991). Once a shark
fishery has collapsed, it takes many decades for the stocks to recover, if they
recover at all.

In the past, most shark fisheries were small artisanal
fisheries that caught whatever species of sharks were locally or seasonally
abundant, or intensive regional fisheries that targeted individual species for
specific products: liver oil in the cases of the soupfin and basking sharks, and
meat in the cases of the porbeagle and school sharks. Fishery administrators and
the public generally had little interest in shark fisheries, because they were
usually small. The rapid growth in the size and value of the shark fisheries
throughout the world, along with increasing shark bycatch and recreational
fishing, and the known vulnerability of sharks to overfishing, have engendered
worldwide concerns and attempts to manage and conserve sharks. In addition to
the economic concerns for a valuable resource, public attitude towards sharks in
some countries has changed dramatically. The conservation ethic and concern for
wildlife have been extended to encompass sharks, and, in many parts of the
world, the public has developed an acute interest in conserving
sharks.

Attempts to manage or conserve sharks have been few, and
usually engendered by economic concerns about declining fisheries. Australia has
had a shark fishery since the turn of the century, and it imposed more
restrictions on licenses and fishing methods in 1988 (Stevens 1993). The sand
tiger shark, Carcharias taurus, received protected status in the
Australian state of New South Wales in 1984 (Pollard 1996). In New Zealand,
shark management started in 1986 over concerns of declining catch per unit
effort (CPUE). In South Africa, the great white shark has been protected since
1991 (Compagno 1991). In the United States, concerns about a rapidly growing
fishery and overfishing led to a fishery management plan for the Atlantic coast
in 1993 (NMFS 1993). Protected status has been given in April 1997 to five
species in the United States on the Atlantic coast: the great white shark; the
whale shark; the basking shark; the sand tiger shark; and the bigeye sand tiger
shark. Shark fisheries along the western coast of the United States for shortfin
mako and thresher sharks have been regulated by state agencies for many years.
In 1989, the states of California, Oregon and Washington enacted an
inter-jurisdictional fishery-monitoring plan for thresher sharks (Hanan et
al. 1993).